Cancer is the second leading cause of death in the United States, exceeded only by heart disease. (Cancer Facts and Figures 2004, American Cancer Society, Inc.). Despite recent advances in cancer diagnosis and treatment, surgery and radiotherapy may be curative if a cancer is found early, but current drug therapies for metastatic disease are mostly palliative and seldom offer a long-term cure. Even with new chemotherapies entering the market, the need continues for new drugs effective in monotherapy or in combination with existing agents as first line therapy, and as second and third line therapies in treatment of resistant tumors.
Cancer cells are by definition heterogeneous. For example, within a single tissue or cell type, multiple mutational “mechanisms” may lead to the development of cancer. As such, heterogeneity frequently exists between cancer cells taken from tumors of the same tissue and same type that have originated in different individuals. Frequently observed mutational “mechanisms” associated with some cancers may differ between one tissue type and another (e.g., frequently observed mutational “mechanisms” leading to colon cancer may differ from frequently observed “mechanisms” leading to leukemias). It is therefore often difficult to predict whether a particular cancer will respond to a particular chemotherapeutic agent (Cancer Medicine, 5th edition, Bast et al., B. C. Decker Inc., Hamilton, Ontario).
Maglignant gliomas cause over 15,000 cancer deaths in the United States each year. These brain tumors are among the most difficult human cancers to treat, even with extensive surgery, radiation therapy and chemotherapy, survival remains poor. The most widely used chemotherapy drug for treating glioma patients is Temodar (Temozolamide). Even with the best current therapy available the probability that a glioblastoma patient will survive at least two years is 9%. Brain edema is also a serious problem for these brain cancer patients and they often require treatment with corticosteroids to reduce the edema, but are then subjected to the common steroidal side effects of immunosuppression, hypertension and steroidal dependence. A major challenge in developing new therapies for treating gliomas and brain metastases is that very few small molecule anti-tumor drugs are capable of penetrating the brain well enough to provide therapeutically effective drug levels. Consequently, the development of more effective drugs for treating brain cancer and brain metastases is a large unmet medical need. The present invention addresses these needs.
Accordingly, new compositions and methods for treating and preventing reoccurrence of proliferation disorders, including cancer, are needed. The present invention addresses these needs.